Sweet Dreams: When Can I Resume Diving Post Anaesthesia?

There is no definite data on how soon patients recover from the blunted sensorium that occurs with general anaesthesia. This is highly variable and influenced by numerous factors, including the type of premedication, the inhalation anaesthetic agent used, the length of the operation, the intra-operative medications administered and any post-operative recovery problems. In the elderly, long-term effects of general anaesthesia have been reported to decrease cognition for up to three months post-operatively.The ability to dive depends on the diagnosis for which the anaesthetic was given and the disability from the surgical procedure will determine when you can resume diving. If one was put to sleep for some non-debilitating diagnosis (e.g. dental procedures) one should be able to resume diving after 24-48 hours. Longer periods of diving cessation may be recommended, depending on the procedure performed and the presence of complications.The drugs used to induce general anaesthesia do not take long for your body to metabolise. It is recommended that at least 24 hours elapse after general anaesthesia before resuming daily activities. Diving should be safe after 48 hours, provided that the patient is not taking any sedatives. Entonox, often used in sedation for minor procedures, has a very short half-life and diving may be resumed after 12-24 hours. After local, spinal or epidural anaesthesia, recovery of full strength and normal sensation in the affected areas are vital.The purpose of the assessment of fitness to return to diving after illness, surgery or injury is primarily to determine any factors which may affect in water safety.Post-Operative RecoveryThe most important hazard is the reduced exercise capacity dependent on the extent of the intervention and any post-operative conditions which could impair diving. Reduced physical fitness after surgery from inactivity and bedrest, pain, restricted function of organs, impairment of the motor system, and anaemia are several factors which play a role.A diver may also put him/herself and his/her dive buddies at risk due to the impairment of his/her physical and psychological performance, owing to the medication being taken post-operatively. Medications which cause central nervous system depression can alter consciousness or hamper the diver’s decision-making ability.Some systemic analgesics and narcotic pain relievers are contraindicated in diving. Their side effects include dizziness, drowsiness, impairment of mental performance and alterations in mood. These are dose-related and the lower the amount, the less frequent and severe the adverse reactions. Opiates can impair psychomotor performance and in high doses are known to cause respiratory depression which will be further potentiated by the narcotic effect of nitrogen as well as the increased work of breathing at depth due to increased gas density. Resultant carbon dioxide retention enhances the risk of oxygen toxicity. Nausea, a common side effect of medication, may further complicate matters. Paracetemol is considered a safe and non-steroidal anti-inflammatory drug and is relatively safe, as no medical contraindication for its use exists.However, the major determinant is not the anaesthetic, but rather the reason for the anaesthetic. Diving is not a good idea immediately after surgery,irrespective of the anaesthetic.When approaching the time to resume diving, one first has to consider the illness or condition being operated on and any relation of it to the diving environment. Any physical limitations as a result of the surgery, either short-term (like the rate that the wound heals and complications such as infection, wound disruption or temporary loss of function) or long-term disability (reducing the diver’s functional ability), should then be considered.Thirdly, implants of any nature should be evaluated. Any air- or gas-filled implant poses a risk of exploding or rupturing, due to the effect of Boyle’s law. Metallic, silicone, composite and fluid-filled sacs do not contain any gas and are therefore not compressible and shouldn’t be a contraindication to diving. The following guidelines are used to advise on the return to diving for selected surgical interventions:Ear, nose and throat surgeriesWhen undergoing septal deviation corrective surgery you should be able to return to diving three months after the successful surgery, provided there is no restricted nasal breathing and normal Eustachian tube function exists.After surgical closure of a tympanic perforation (tympanoplasty), you may resume diving three months following the surgery, if the transplant has healed well and the Eustachian tube function is normal. Any extensive surgery on the middle ear and mastoid present a definite contraindication for diving due to the danger of tympanic rupture and prosthesis dislocation which will likely result in deafness. This includes hearing improving surgery.Surgery of the lips, oral cavity, palate, or upper and lower jaw may cause insufficient hold and/or sealing of the regulator mouthpiece, which may predispose the diver to aspiration and panic. Therefore, candidates should perform a test dive and be able to hold and seal off the mouthpiece.Respiratory surgeriesPulmonary resection leads to differences in flow resistance and lung distensibility with the risk of lung barotrauma. After segmental resection or lobectomy, diving may be permitted three months post-operatively. Vital capacity should be 70-80% of the normal value with normal lung function testing results (FEV1/FEV; FVC at least 0.7). This decision must be made in consultation with a pulmonologist, preferably with diving medicineexperience. A pneumonectomy (excision of the lung or one or more lobes)resection with a vital capacity less than 70% of the nominal value is an absolute contraindication to diving.Special considerations on an individualised basis are taken in cases where barotrauma of the lungs (“burst lung”) has been surgically treated through pleurectomy (surgical excision of the lung pleura), but, in general, an incident of pulmonary barotrauma is a contraindication for further scuba diving and in most cases it is advised not to continue diving.Pleurodesis (obliteration of the pleural cavity) ensures protection from a pneumothorax, but at the expense of an increasing risk of a cerebral arterial gas embolism (CAGE) and mediastinal emphysema.Patients who have had a thoracotomy can be certified for diving after thorough evaluation by a thoracic surgeon knowledgeable of diving medicine. A post-operative wait of 12 weeks is advised, including studies to rule out air trapping.Cardiovascular surgeriesFollowing any cardiac surgery with entry into the chest cavity, with no symptoms and a normal exercise test with normal haemodynamics and no rhythm disturbances, you may be cleared for diving three to six months postoperatively in consultation with the relevant specialist.After surgery without entering the chest cavity, a six to eight week waiting period is advised or whenever the diver has physically rehabilitated to reach 13 metabolic equivalents (METs) on the treadmill. With peripheral revascularisation surgery, one can resume diving as soon as the wounds have healed and no symptoms are experienced. Long-term anti-coagulation therapy does not represent any specific danger to diving and is not a contraindication to diving, but can lead to dangerous haemorrhages and therefore poses an increased bleeding risk and possibly worse outcomes in cases of trauma, barotrauma of the ear, sinuses or lungs, and spinal decompression sickness (DCS).Nervous system surgeriesAfter successful treatment of aneurysms of the cerebral vessels and clearance from the neurosurgeon, one may be permitted to dive.Any craniotomy (surgical opening of the skull) that is not definitely closed is anabsolute contraindication to diving. Burr hole cases or any complete reconstruction of the cranial vault and ventriculo-peritoneal (VP)- or ventriculo-atrial (VA)-shunts should allow a period of six months and be free of any residual symptoms or epileptic fits.Internal organ surgeriesPeople with stomas or indwelling urethral catheters are able to dive, provided they have received thorough counselling regarding hygiene problems and personal care.After surgical correction of a hernia, six weeks (in simple cases) to three months should be allowed before returning to diving. The patient should also be warned about lifting heavy dive gear and the risk of recurrence of the hernia.The post-operative wait after laparotomy depends greatly upon the cause for the surgery and the extent of the surgery involved. A post-operative period of six to 12 weeks is recommended, with approval by the surgeon.With gynaecological procedures, as a rule, six weeks is needed followed by a follow-up and clearance by the specialist. Otherwise, diving can resume when the vaginal stump has healed.In all cases, the diver should be self-sufficient with adequate exercise capacity and fitness following complete healing, complete rehabilitation, have normal swimming ability and be able to assist his/her buddy, if necessary.Musculoskeletal surgeriesAfter conservative or surgical treatment of joint dislocations or instabilities and fractures, diving may be resumed following the complete healing with normal swimming ability and no restrictions of function. This usually suggests a period of six weeks to three months with clearance from the relevant surgeon.Weight-bearing, exits and entries should be carefully considered before certifying the return to diving.Eye surgeriesParticular caution should be exercised in cases following intraocular surgery, because negative pressure could lead to a dehiscence of the operation scar with grave consequences.After cataract surgery, dehiscence of the corneoscleral scar may be a risk and therefore a post-operative period of three months should be allowed before returning to diving. A six-to-12-month period is suggested following penetrating keratoplasty and radial keratoplasty and three months are suggested for lamellar keratoplasty.It is recommended that divers wait a minimum of one month before resuming diving after laser-assisted in situ keratomileusis (LASIK) refractive surgery.Plastic surgeryA three-to-six-month waiting period is advised after breast augmentation surgery. Botulinum toxin injections, used for cosmetic purposes, can in some cases prevent adequate sealing of the mouthpiece.In SummaryWhether or not a person who has had surgery should be certified as “fit to dive” should be decided on the merits of each case.Returning to diving depends mainly on the type of surgery performed, whether the diver is symptomatic, the medication requirements, the restrictions placed on the patient by the surgical procedure and the length of time the diver is post-operatively free of problems. Most candidates can probably return to diving. Of greatest importance is the impact on safety. Apart from the general condition and physical fitness, the following should be taken into consideration: decision-making ability, the ability to self-rescue and rescue other divers as well as residual disabilities that would limit the diver’s ability to gear up and move in the water. Prospective divers should in all cases provide full disclosure to the dive instructor and certifying agency, bearing in mind the safety of their buddies, dive instructors, dive masters and other individuals who are also affected by diving incidents.An evaluation should be done by the relevant medical specialist, preferably in consultation with a diving medicine practitioner, if he/she is not experienced in diving medicine.A test dive is also recommended before planning a diving holiday when returning to diving after surgery or anaesthesia.References & Suggested Reading

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